The present invention relates generally to radio communication systems, and in particular, to integrating multiple services in a radio communication system.
Radio communication systems providing multiple services, such as interconnect and dispatch services, are known. In such multi-service systems, an interconnect service provides an interface to the public switched telephone network (PSTN) permitting calls to be placed between radio mobile subscriber units (MSUs) and conventional telephones using the PSTN.
The dispatch service permits MSUs to communicate with one another using standard dispatch protocols over a shared communication channel. In dispatch subsystems, MSUs are organized into talk groups according to geographic location. Among other things, conventional dispatch services provide for group calls and private calls between MSUs.
A disadvantage of currently available multi-service systems is that interconnect and dispatch services are not fully integrated. This results in a number of limitations. In the case of mobile-to-mobile interconnect calls between MSUs, currently available multi-service systems employ the PSTN and transcoder resources of the interconnect service. Each interconnect call between two MSUs requires two voice processors of the transcoder. This results in a call having a longer set-up time and consuming more system resources.
Another limitation of known multi-service systems is that there is not inter-service notification of MSU statuses. Thus, if a subscriber initiates a dispatch call to an MSU involved in an interconnect call, the dispatch subsystem will simply attempt to page the busy MSU without the ability to notify either the busy MSU or the caller. A similar scenario occurs during an interconnect call request to an MSU involved in a dispatch call. System bandwidth and resources are wasted by paging unreachable MSUs.
The lack of inter-service notification also prevents MSUs in dispatch mode from receiving call waiting notification of incoming interconnect calls, and vice versa.
Another problem with known multi-service systems is that interconnect subsystems and dispatch subsystems are not directly connected. This can negatively affect the overall reliability and performance of the communication system because a failure in one subsystem will not be detected by the other subsystem.
Therefore, a need exists for a multi-service radio communication system that more fully integrates services and subsystems so as to overcome the limitations discussed above.